Technical Field
The present disclosure relates to an airbag device for a front passenger seat.
Related Art
Japanese Patent Application Laid-Open (JP-A) No. 2015-113027 discloses a front seat airbag system that is appropriate for oblique collisions and small overlap collisions (details of these collision states are described in the Detailed Description section). In this front seat airbag system, an additional center airbag is specified adjacent to the vehicle width direction inner side of a front passenger seat airbag (the side thereof at which a center console is disposed). The center airbag is provided separately and independently of the front passenger seat airbag. A completely expanded shape of the center airbag is designed such that a rear end portion of the center airbag protrudes further to the vehicle rear side than a rear end portion of the front passenger seat airbag. In this conventional technology, in order to improve head protection performance for a vehicle occupant sitting in a driver seat when there is an impact against the vehicle from diagonally forward, at the front passenger seat side of a vehicle front portion, a structure is employed in which the center airbag is structured separately and independently of the front passenger seat airbag and the two airbags are linked by a tear seam. In the descriptions below, a vehicle occupant sitting on a driver seat is referred to as “the driver seat occupant”, and a vehicle occupant sitting on a front passenger seat is referred to as “the passenger seat occupant”.
According to the structure described above, when, for example, there is an impact against the vehicle from diagonally forward at the driver seat side of the vehicle front portion, the front passenger seat airbag inflates and expands toward the side thereof at which the passenger seat occupant is disposed, and the center airbag inflates and expands to the vehicle width direction inner side (the center console side) of the front passenger seat airbag. In a completely expanded state, the rear end portion of the center airbag is disposed to protrude further to the vehicle rear side than the rear end portion of the front passenger seat airbag. Therefore, a side face of the center airbag that faces toward the side thereof at which the front passenger seat airbag is disposed functions as a restraining surface for the passenger seat occupant's head. Thus, even though the head of the passenger seat occupant moves by inertia in the direction toward the side of the impact at the vehicle front portion (diagonally toward the vehicle front and the side at which the center console is disposed), the head of the passenger seat occupant is restrained by both a rear end face of the front passenger seat airbag and the side face of the center airbag (see paragraphs 0070 to 0072 in the Specification of JP-A No. 2015-113027).
The conventional technology described above is effective as a vehicle occupant head protection technology when there is an oblique collision, a small overlap collision or the like. However, in the conventional technology as described above, the structure is employed in which the center airbag is structured separately and independently from the front passenger seat airbag and the two airbags are linked by a tear seam. Therefore, if there is an oblique collision, a small overlap collision or the like against the front passenger seat side of the vehicle front portion, then when the head of the passenger seat occupant is being restrained, the restraining surface of the front passenger seat airbag and the restraining surface of the center airbag may be moved apart and open a gap. In this situation, when the head of the passenger seat occupant abuts against the restraining surface of the font passenger seat airbag, the head of the passenger seat occupant is subjected to a frictional force from this restraining surface, and this frictional force may apply a turning moment about an axis in the vehicle up-and-down direction to the head of the passenger seat occupant.
As a countermeasure, forming the center airbag integrally with the front passenger seat airbag such that the center airbag does not separate from the front passenger seat airbag has been considered. However, in this case, an amount of gas required to inflate and expand the front passenger seat airbag is increased by an amount required for the center airbag. Thus, inflation and expansion of the front passenger seat airbag if there is a full overlap frontal collision is slowed.
Moreover, in a design in which a projection to the vehicle interior, such as a display or the like, is set at a vehicle width direction central portion of an instrument panel, a center airbag portion of the front passenger seat airbag may catch on the vehicle interior projection while expanding, which may affect the inflation and expansion of the front passenger seat airbag. Thus, a problem arises in that the shape of the restraining surface of the front passenger seat airbag may not be formed in accordance with objectives.
In consideration of the circumstances described above, a first object of the present disclosure is to provide an airbag device for a front passenger seat that may improve head protection performance for a passenger seat occupant when an impact occurs that is any of an oblique collision against the driver seat side of a vehicle front portion or a small overlap collision (hereinafter shortened to “when there is an oblique impact against the driver seat side or the like”), and that may also assure head restraint performance for the passenger seat occupant when there is a full overlap frontal collision. In addition, in consideration of the circumstances described above, a second object of the present disclosure is to provide an airbag device for a front passenger seat with which inflation and expansion of a front passenger seat airbag is not impeded even if a design is employed in which there is a projection to the vehicle interior at a vehicle width direction central portion of an instrument panel.